title: Cold shock CspA and CspB protein production during periodic temperature cycling in Escherichia coli.
abstract: BACKGROUND
  Temperature is an important environmental factor which can dramatically affect biochemical processes in bacteria. Temperatures above optimal cause heat shock, while low temperatures induce cold shock. Since the physiological response of the bacterium Escherichia coli to slow temperature fluctuation is not well known, we investigated the effect of periodic temperature cycling between 37° and 8°C with a period of 2 h on proteome profile, cold shock CspA and CspB protein and gene production.
  
  
  RESULTS
  Several proteins (i.e. succinyl-CoA synthetase subunit alpha, periplasmic oligopeptide-binding protein, maltose-binding periplasmic protein, outer membrane porin protein, flavodoxin-1, phosphoserine aminotransferase) were up or down regulated during temperature cycling, in addition to CspA and CspB production. The results indicate that transcription of cspA and cspB increased during each temperature downshift and consistently decreased after each temperature upshift. In sharp contrast CspA-FLAG and CspB-FLAG protein concentrations in the cell increased during the first temperature down-shift and remained unresponsive to further temperature fluctuations. The proteins CspA-FLAG and CspB-FLAG were not significantly degraded during the temperature cycling.
  
  
  CONCLUSIONS
  The study demonstrated that slow periodic temperature cycling affected protein production compared to cells constantly incubated at 37°C or during classical cold shock. Bacterial cspA and cspB mRNA transcript levels fluctuated in synchrony with the temperature fluctuations. There was no corresponding pattern of CspA and CspB protein production during temperature cycling.
authors.affiliation: Laboratory of Microbiology, Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, 1000 Ljubljana, Slovenia.
authors.forename: Tina
authors.initials: T
authors.lastname: Ivancic
authors.forename: Polona
authors.initials: P
authors.lastname: Jamnik
authors.forename: David
authors.initials: D
authors.lastname: Stopar
mesh_terms: D001483:Base Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000096:biosynthesis*; D057773:Cold Shock Proteins and Peptides / Q000096:biosynthesis*; D017931:DNA Primers; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000096:biosynthesis*; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D016601:RNA-Binding Proteins; D060888:Real-Time Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature
chemical_list: D002352:Carrier Proteins; D057773:Cold Shock Proteins and Peptides; C498192:CspA protein, E coli; C491179:CspB protein, E coli; D017931:DNA Primers; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D016601:RNA-Binding Proteins